JP2007255844A - Fusing equipment and fusing method of gasification fusing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly operate fusing equipment by preventing the cooling of a slag cinder notch by water vapor generated from a water granulation tank and troubles to appliances such as an auxiliary burner. <P>SOLUTION: In this fusing equipment 1 of the thermal decomposition gasification system composed of a rotary fusing furnace 2 comprising a thermal decomposition gas burner 3, the slag cinder notch 6, and a slag extraction chute 7 extending from the slag cinder notch 6 to the water granulation tank 20, and a secondary combustion chamber 15 disposed at an upper portion of the rotary fusing furnace, the lower end of the slag extraction chute 7 is dipped in the water granulation tank 20 to form a water seal, the lower end 7a of the slat extraction chute extends to a lower portion with respect to a water level position displaced by the fall of fused slag to the water granulation tank 20, a bypass passage 10 communicated from the slag extraction chute 7 to the secondary combustion chamber 15 is formed, and at least a part of a water vapor-containing gas 13 including the water vapor evaporated from the water granulation tank 20 is led from the slag extraction chute 7 to the secondary combustion chamber 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a melting technique in a gasification melting system in which waste is pyrolyzed to generate pyrolysis gas and ash is melted by the combustion heat of the pyrolysis gas, and in particular, a granulation tank that granulates molten slag. The present invention relates to a melting facility and a melting method of a gasification and melting system that can prevent a malfunction from occurring in a melting facility due to water vapor evaporated from the gas and can perform a smooth operation.

Conventionally, a gasification and melting system is known as a technology capable of processing a wide range of wastes such as municipal waste, non-combustible waste, incineration residue, sludge, landfill waste and the like.
An outline of the gasification melting system is shown in FIG. The gasification melting system includes a gasification furnace 33 that thermally decomposes and gasifies waste, and a pyrolysis gas 53 that is provided downstream of the gasification furnace 33 and is generated in the gasification furnace 33 at a high temperature. In addition, a melting facility 1 for melting ash in gas into slag is provided, and in order to make waste resources, reduce the volume and make it harmless, the slag is taken out from the melting facility 1 and civil engineering such as roadbed materials It is reused as a material, or waste heat is recovered from exhaust gas discharged from the melting facility 1 to generate power (see Patent Document 1).

  As one of the melting facilities 1, there is an apparatus provided with a vertical swirl melting furnace 2. The vertical swirl melting furnace 2 is provided with a pyrolysis gas burner for blowing the pyrolysis gas 53 into the melting furnace and a combustion air supply nozzle for introducing the combustion air 54, and the pyrolysis ejected from the pyrolysis gas burner. The gas 53 burns combustible components while forming a swirling flow in the furnace, and melts inorganic components. The molten slag adheres to the inner wall of the furnace due to the centrifugal force generated by the swirling flow, flows down along the wall surface, is discharged from the slag outlet, and falls to the granulation tank 20 through the extraction chute 6. Cooling water is stored in the water granulating tank 20, and the molten slag that has fallen into the cooling water is rapidly cooled to be granulated and recovered as granulated slag. On the other hand, the exhaust gas generated by the combustion is sent to the secondary combustion chamber 15 through the connecting portion 5 of the throttle structure, and after the unburned portion is combusted in the secondary combustion chamber 15, the exhaust gas treatment facility passes through the boiler 17. Sent to.

  In such a melting facility, the exhaust gas generated in the furnace is guided to the upper secondary combustion chamber, so the slag outlet is not used for the slag outlet located below, and the slag outlet is sufficiently Since it is not heated, molten slag may adhere to the furnace wall and become blocked. Therefore, various techniques have been proposed to prevent this. For example, in Patent Document 2 (Japanese Patent Laid-Open No. 2000-205546), a bypass pipe that directly connects a slag discharge pipe and a secondary combustion chamber is provided, and high-temperature combustion exhaust gas in the furnace is subjected to secondary combustion via the slag discharge pipe. The slag discharge pipe is maintained at a high temperature. Similarly, in Patent Document 3 (Japanese Patent Laid-Open No. 11-63437), the dry distillation gas in the melting furnace is guided from the downstream side of the slag outlet to the secondary combustion chamber via the exhaust gas passage, and the slag outlet It is set as the structure which prevents the cooling of.

JP 2004-144402 A JP 2000-205546 A JP-A-11-63437

As a method for preventing cooling of the slag outlet, a method has been proposed in which high-temperature combustion exhaust gas in the furnace is extracted from the outlet side and bypassed and guided to the secondary combustion chamber, as described in Patent Documents 2 to 3. Yes.
However, as a cause of cooling the slag outlet, it can be considered that the slag outlet is cooled by steam evaporated from the granulation tank, in addition to the fact that the sensible heat of the high-temperature combustion exhaust gas cannot be used. That is, when recovering granulated slag, a granulating tank storing cooling water is installed below the slag extraction chute, but when hot molten slag falls into the granulating tank, the cooling water evaporates and a large amount Water vapor is generated. In particular, in a melting facility in a pyrolysis gasification system, generally, the inside of the furnace is maintained at a negative pressure, so that steam is likely to be generated, and since the slag outlet is a closed system, the slag is discharged without being diffused. The water vapor remains in the well and the melting furnace, and this water vapor cools the slag outlet and the slag extraction chute, and the molten slag may solidify and become blocked.

In addition, the auxiliary burner installed to heat the slag outlet may be condensed due to the water vapor, resulting in a malfunction, and a malfunction may occur in the equipment installed in the slag extraction chute. It is done.
However, in the apparatuses described in Patent Documents 2 and 3, no measures have been taken for cooling of the slag extraction chute caused by water vapor or for malfunctions of the equipment, and in particular, Patent Document 3 is applied to the gasification and melting system. Since it is not an apparatus, it is considered that it is not considered that a large amount of water vapor is generated by bringing the melting equipment into a negative pressure state as in the gasification melting system.
Therefore, in view of the above-mentioned problems of the prior art, the present invention can prevent problems with equipment such as cooling of slag outlets and auxiliary burners due to water vapor generated from the granulation tank, and enables smooth operation of the melting facility. An object is to propose a melting equipment and a melting method in the gasified melting system.

Therefore, in order to solve this problem, the present invention provides:
A pyrolysis gas burner for introducing a pyrolysis gas generated by pyrolyzing waste, a slag outlet for discharging molten slag generated by melting ash by the combustion heat of the pyrolysis gas, and the slag discharge A pyrolysis comprising a swirl melting furnace provided with a slag extraction chute extending from the shed to the water granulation tank, and a secondary combustion chamber disposed above the swirl melting furnace via a connecting portion In the melting equipment of the gasification system,
The lower end of the slag extraction chute is immersed in the water granulation tank to form a water seal, and the lower end of the slag extraction chute extends downward from the water surface position displaced by the fall of the molten slag into the granulation tank. And
A bypass passage communicating from the slag extraction chute to the secondary combustion chamber is provided, and at least a part of the steam-containing gas including water vapor evaporated from the granulation tank is guided from the slag extraction chute to the secondary combustion chamber. It is characterized by that.

According to the present invention, the water vapor generated from the granulation tank due to the fall of the molten slag can be released to the secondary combustion chamber above the swirling melting furnace, so there are a large amount of slag outlet, slag extraction chute and auxiliary burner. Therefore, it is possible to prevent problems such as blockage due to cooling of the slag outlet and the slag extraction chute and failure due to condensation of the auxiliary burner. Further, it is possible to prevent water vapor from entering the swirl melting furnace above the slag extraction chute and to smoothly operate without hindering the formation of swirl flow.
Moreover, since the lower end of the extraction chute is extended longer than before, the water seal can be reliably maintained even when the water surface is rippled due to the fall of the molten slag.

Further, an auxiliary burner for heating the slag outlet is provided on the slag extraction chute.
In this way, the slag outlet is heated by the auxiliary burner to prevent cooling of the slag outlet, and according to the present invention, the bypass passage is provided to release the water vapor. Therefore, it is possible to prevent a failure due to condensation of the auxiliary burner.

Furthermore, the inside of the swirl melting furnace including the slag extraction chute is maintained in a negative pressure state.
Thus, by maintaining the inside of the furnace in a negative pressure state, it is possible to promote the formation of a swirl flow in the swirl melting furnace and maintain a good combustion state. Moreover, although the generation | occurrence | production of the water vapor | steam from a granulation tank increases by making the inside of a furnace into a negative pressure state, the cooling by a water vapor | steam and a malfunction can be prevented by providing a bypass channel like this invention.
Further, in the present invention, since the secondary combustion chamber is provided via the connecting portion opened above the swirl melting furnace, the negative pressure is higher in the secondary combustion chamber than in the slag extraction chute. . Therefore, the steam-containing gas is easily conveyed from the slag extraction chute to the secondary combustion chamber through the bypass passage, and the steam removal efficiency can be increased.

Furthermore, the bypass passage is provided below the slag extraction chute and in the vicinity of the water surface of the granulating tank.
Thereby, most of the water vapor can be led to the secondary combustion chamber side, and cooling and malfunction due to the water vapor can be further prevented.

Also, ash is melted in a swirling melting furnace by the combustion heat of pyrolysis gas generated by pyrolyzing waste, and the molten slag generated by the melting is granulated through a slag extraction chute and through a slag extraction chute. In the melting method of the pyrolysis gasification system, the exhaust gas generated in the swirling melting furnace is guided to the secondary combustion chamber above the melting furnace while being discharged into the tank.
The lower end of the slag extraction chute is immersed in the granulation tank to form a water seal, and at least a part of the steam-containing gas including water vapor evaporated from the granulation tank is extracted through the bypass passage. It leads to the secondary combustion chamber from a chute.
Furthermore, an induction fan installed on the rear stage side of the swirl melting furnace is controlled so that the inside of the swirl melting furnace including the slag extraction chute is maintained in a negative pressure state.

  As described above, according to the present invention, the water vapor generated from the granulation tank due to the fall of the molten slag can be released to the secondary combustion chamber above the swirl melting furnace. The burner is not exposed to a large amount of water vapor, and it is possible to prevent equipment malfunctions such as blockage due to cooling of the slag outlet and the extraction chute and failure due to condensation of the auxiliary burner. Therefore, smooth operation of the gasification melting system is possible.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
FIG. 1 is a configuration diagram showing a side cross section of a melting facility according to an embodiment of the present invention, FIG. 2 is an enlarged side view showing a granulation tank of FIG. 1, and FIG. 3 is a diagram of a gasification and melting system according to an embodiment of the present invention. It is the schematic which shows the whole structure.

First, a schematic configuration of the gasification melting system according to the present embodiment will be described with reference to FIG.
The waste 50 input from the waste input hopper 31 is crushed and dried as necessary, and then quantitatively supplied to the fluidized bed gasifier 33 through the dust feeder 32. In the fluidized bed gasification furnace 33, combustion air 51 having a temperature of about 120 to 230 ° C. and an air ratio of about 0.2 to 0.7 is blown into the furnace through the wind box 34 from the lower part of the furnace, and the fluidized bed temperature is 550. It is maintained at about ˜650 ° C.
The waste 50 is pyrolyzed and gasified in the fluidized bed gasification furnace 33 and decomposed into gas, tar, and char (carbide). Tar is a component that becomes liquid at room temperature, but is present in a gaseous state in the gasification furnace. The incombustible material 52 of the gasification furnace 33 is sequentially discharged from the incombustible material discharge port 35.
The char is gradually pulverized in the fluidized bed, and is introduced into the vertical swirl melting furnace 2 of the melting facility 1 along with gas and tar. Hereinafter, these components introduced into the swirl melting furnace 1 are collectively referred to as a pyrolysis gas 53. The melting facility 1 includes a swirl melting furnace 2, a secondary combustion chamber 15 disposed above the swirl melting furnace 2, and a boiler unit 17 disposed on the downstream side of the secondary combustion chamber 15. It consists of.

The pyrolysis gas 53 discharged from the top of the fluidized bed gasification furnace 33 is introduced into the pyrolysis gas burner of the swirling melting furnace 2 through a lining duct. In the pyrolysis gas burner, pyrolysis gas 53 is mixed with combustion air 54 and introduced into the furnace to form a swirling flow. At this time, the combustion air may have an air ratio of 0.9 to 1.1, preferably about 1.0.
In the swirling melting furnace 2, the mixed gas of the pyrolysis gas 53 and the combustion air 54 is combusted, so that the furnace temperature is maintained at 1300 to 1500 ° C., and the ash content in the pyrolysis gas 53 is melted and slagged. The molten slag adheres and flows down on the inner wall surface of the swirl melting furnace 2 and is discharged from the slag outlet 6 at the bottom of the furnace through the slag extraction chute 7. The slag discharged from the slewing melting furnace 2 is rapidly cooled in the granulation tank 20, carried out by the slag conveyor 21, and collected as granulated slag. The recovered granulated slag can be effectively used for roadbed materials and the like.

On the other hand, the combustion exhaust gas discharged from the swirl melting furnace 2 is introduced into the secondary combustion chamber 15 via the connecting portion 5. In the secondary combustion chamber 15, the combustion air 55 is supplied so as to have an air ratio of 1.2 to 1.5, and unburned components in the combustion exhaust gas are completely burned here.
The combustion exhaust gas is heat recovered by the boiler unit 17 and cooled to about 250 ° C. The combustion exhaust gas discharged from the boiler unit 17 is introduced into the temperature reducing tower 36 and is cooled to about 150 ° C. by direct water spray. The combustion exhaust gas discharged from the temperature reducing tower 36 is sprayed with slaked lime and activated carbon in the flue as necessary, and is introduced into the reaction dust collector 37. The reaction dust collector 37 removes soot, acid gas, DXNs and the like in the combustion exhaust gas. The dust ash discharged from the reaction dust collector 37 is treated with chemicals and disposed of in landfill. The combustion exhaust gas is reheated by the steam heater 38 and NO _x is removed by the catalyst reactor 39. Through the chimney 41.

Next, the melting equipment 1 in the present embodiment will be specifically described with reference to FIG.
As shown in the figure, the melting facility 1 has a swirl melting furnace 2 having a circular cross section, and one or a plurality of pyrolysis gas burners 3 for blowing a pyrolysis gas 53 into the side wall of the swirl melting furnace 2. The pyrolysis gas burner 3 is provided with a combustion air supply nozzle 4 for introducing combustion air (primary air) 54. An auxiliary combustion burner (not shown) is disposed in the vicinity of the pyrolysis gas burner 3. Further, the upper portion of the furnace body 2 communicates with the secondary combustion chamber 15 via the connecting portion 5 having a throttle structure, and the combustion exhaust gas generated in the swirling melting furnace 2 is sent to the secondary combustion chamber 15. Yes. A slag outlet 6 is provided at the bottom of the swirl melting furnace 2, and the molten slag is discharged through a slag extraction chute 7 extending downward from the slag outlet 6. An auxiliary burner 8 is attached to the slag outlet chute 7 toward the slag outlet 6 and has a function of keeping the molten slag discharged from the slag outlet 6 solidified and not blocked. Yes. Examples of the auxiliary fuel 57 supplied to the auxiliary burner 8 include kerosene, LPG, city gas and the like, and it is desirable to use oxygen having a purity of 90% or more instead of combustion air.

  As shown in FIG. 2, a granulation tank 20 is installed below the slag extraction chute 7, and cooling water 24 is stored in the granulation tank 20. The lower end 7 a of the slag extraction chute 7 is immersed in the cooling water 24 and seals the slag extraction chute 7 with water. In addition, a slag conveyor 21 is immersed in the water granulating tank 20 to receive and transport the molten slag that has fallen from the slag extraction chute 7. The molten slag is cooled and crushed by the cooling water 24 while being transported, and then discharged from the pulverized slag discharge port 22 to be recovered as the granulated slag 56. The granulated slag 56 is stored in the slag storage unit 23.

  As a characteristic configuration of the present embodiment, the lower surface 7a of the slag extraction chute is immersed in the granulation tank 20 to form a water seal, and the lower surface 7a is displaced by the fall of the molten slag into the granulation tank 20. It extends so as to extend downward from the position. Further, the induction fan 40 in the subsequent stage is controlled so that the inside of the melting facility 1 including the slag extraction chute 7 is maintained in a negative pressure state. Since the inside of the melting facility 1 is in a negative pressure state, the water surface in the slag extraction chute 7 is located higher than the surrounding water surface, but reaches a position lower than the displacement of the water surface including the height difference of the water surface. Until the slag extraction chute lower end 7a is extended. Thus, by making the slag extraction chute lower end 7a longer than before, even when the water surface of the granulation tank 20 is rippled due to the fall of the molten slag, the water seal can be reliably maintained, A negative pressure state can be maintained.

  Furthermore, in this embodiment, a configuration is provided in which a bypass passage 10 communicating from the slag extraction chute 7 to the secondary combustion chamber 15 is provided. The inlet 11 of the bypass passage is set to a position where water vapor evaporating from the granulating tank 20 is extracted, and at least a part of the water vapor-containing gas 13 containing the water vapor is guided to the secondary combustion chamber 15. Preferably, the bypass passage inlet 11 is positioned in the vicinity of the water surface of the granulating tank 20. Further, the bypass passage outlet 12 is above the connecting portion 5 of the throttle structure and below the secondary combustion chamber 15.

  According to this configuration, the water vapor generated from the granulation tank due to the fall of the molten slag can be released to the secondary combustion chamber 15 above the swirl melting furnace 1, so that the slag tap port 6, the extraction chute 7 and the auxiliary The burner 8 is not exposed to a large amount of water vapor, and it is possible to prevent malfunctions of the device such as blockage due to cooling of the slag outlet 6 and the extraction chute 7 and failure due to condensation of the auxiliary burner 8. Therefore, smooth operation of the gasification melting system is possible.

It is a block diagram which shows the side cross section of the fusion equipment which concerns on the Example of this invention. It is an enlarged side view which shows the granulation tank of FIG. It is the schematic which shows the whole structure of a gasification melting system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Melting equipment 2 Vertical swirl melting furnace 3 Pyrolysis gas burner 5 Connection part 6 Slag outlet port 7 Slag extraction chute 7a Slag extraction chute lower end 8 Auxiliary burner 10 Bypass passage 13 Steam-containing gas 15 Secondary combustion chamber 20 Granulation Tank 21 Slag conveyor

Claims (6)

A pyrolysis gas burner for introducing a pyrolysis gas generated by pyrolyzing waste, a slag outlet for discharging molten slag generated by melting ash by the combustion heat of the pyrolysis gas, and the slag discharge A pyrolysis comprising a swirl melting furnace provided with a slag extraction chute extending from the shed to the water granulation tank, and a secondary combustion chamber disposed above the swirl melting furnace via a connecting portion In the melting equipment of the gasification system,
The lower end of the slag extraction chute is immersed in the water granulation tank to form a water seal, and the lower end of the slag extraction chute extends downward from the water surface position displaced by the fall of the molten slag into the granulation tank. And
A bypass passage communicating from the slag extraction chute to the secondary combustion chamber is provided, and at least a part of the steam-containing gas including water vapor evaporated from the granulation tank is guided from the slag extraction chute to the secondary combustion chamber. A melting facility for a gasification melting system.   The melting equipment for a gasification melting system according to claim 1, wherein an auxiliary burner for heating the slag outlet is provided on the slag extraction chute.   The melting equipment for a gasification melting system according to claim 1, wherein the inside of the swirl melting furnace including the slag extraction chute is maintained in a negative pressure state.   The melting facility of the gasification melting system according to claim 1, wherein the bypass passage is provided below the slag extraction chute and in the vicinity of the water surface of the granulation tank. Ashes are melted in a swirling melting furnace by the combustion heat of pyrolysis gas generated by pyrolyzing waste, and the molten slag generated by the melting is extracted from the slag outlet to the granulation tank through a slag extraction chute. In the melting method of the pyrolysis gasification system that discharges the combustion exhaust gas generated in the swirl melting furnace to the secondary combustion chamber above the melting furnace,
The lower end of the slag extraction chute is immersed in the granulation tank to form a water seal, and at least a part of the steam-containing gas including water vapor evaporated from the granulation tank is extracted through the bypass passage. A melting method of a gasification melting system, characterized in that the chute is led to the secondary combustion chamber. 6. The thermal decomposition according to claim 5, wherein an induction fan installed on the rear stage side of the swirl melting furnace is controlled so that the inside of the swirl melting furnace including the slag extraction chute is maintained in a negative pressure state. Method of melting gasification system.

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